A pachycaul tree of the Malvaceae (formerly Bombacaceae) described by (Kunth) Dugand in 1943, native to the tropical dry forests of southern Mexico, Central America, and the Greater Antilles. The English common name "Shaving brush tree" captures its signature display: bursts of hot-pink — sometimes white — brush-shaped flowers open on bare branches at night, each carrying around 400 long stamens, and drop by the following morning as one-day blooms. Wild trees reach 18 m, but the grey-white, swollen trunk thickens early even in seedlings, so a caudex-like form develops fast in pots — making this one of the more accessible entry points into caudex growing.
Native climate
Rain concentrates in the warm season, with a distinct dry season. Overall a warm climate.
A broad-scale picture of the native range. Real growing spots — rock crevices, fog belts — can be milder.
Sources: climate & elevation WorldClim 2.1 (1970–2000) · occurrences GBIF · native range POWO
Care
Light & Placement
Native to the selva baja caducifolia (tropical deciduous dry forest) of southern Mexico through Central America, it craves strong sun. Outdoors in full sun during the growing season the trunk stays tight and the petioles short, holding form well. In Japan's midsummer the combination of high heat and direct sun can scorch leaves, so light shading at around 30% with the pot raised on a bench for airflow is the safer setting. After leaf-drop, move it early to a bright indoor window kept above 10°C — never leave it outside through the cold months.
Watering
In active growth, water thoroughly once the surface dries — alternating wet and dry plumps the trunk. Don't leave water in the saucer. After leaf-drop, hold essentially dry through dormancy with at most a monthly misting.
Substrate
Drainage first, inorganic-led. Akadama : Kanuma : pumice = 4:3:3. A taller pot helps keep wet–dry cycles clean and the swollen trunk healthy.
Fertilizer & Supplements
A diluted liquid feed once or twice a month in active growth, or a pinch of slow-release at repotting. The species grows fast and the trunk thickens noticeably in response to modest feeding.
Temperature & Overwintering
Active growth runs 22–35°C; aim for a 10°C minimum. The plant is genuinely cold-sensitive — exposure below 5°C frequently damages or kills the trunk. Move it under cover early in autumn and overwinter dry on a bright indoor window.
Starting from Seed
Where to source seeds
Pre-sowing treatment
Soak seeds for about half a day (overnight) in a mix of a registered seed-treatment fungicide (Benlate or Daconil) and a plant tonic (Menedael; outside Japan, SUPERthrive or a chelated iron / seaweed extract works similarly), each diluted per label. Any that stay afloat are likely no longer viable. Seeds are small and slippery — tweezers help with placement.
Substrate
A fine-grained, near-sterile seedling mix: fine Akadama, fine Kanuma, vermiculite in 1:1:1 parts. Sterilize with boiling water or a microwave pass for safety.
Sowing method
Seeds are small and dark, so sow with no covering or only the thinnest dusting that keeps them partly visible. Space at least 1 cm apart to avoid crowding.
Light & temperature
Bright shade at a steady 25–30°C. Expect germination in 7–21 days. Germination depends strongly on seed freshness, but fresh seed tends to come up well.
Watering
Bottom-water with the level 1–2 cm up the pot. For the first 2–3 weeks, don't let things dry out, then drop the level gradually as seedlings come up.
Fertilizer
No feeding right after germination. Once true leaves emerge, give a heavily diluted liquid fertilizer once or twice a month — growth is brisk without pushing the dose.
From Germination to Repotting
Germination through true leaves
Continue bottom watering, avoid strong light.
Weaning off bottom watering
Transition gradually over 1–2 months.
First repotting
In the first year, once the plant has become root-bound.
Common Pitfalls
Mold & damping-off
- Cause: excess moisture, contamination, poor air flow
- Prevention: sterilize substrate, change bottom water frequently
Etiolation
- Cause: insufficient light, heat-and-humidity stress
- Prevention: bring LEDs closer right after germination, or move to bright shade outdoors
Seeds fail to germinate
- Cause: stale seed, insufficient warmth
- Prevention: fresh seed and 25–30°C on a heat mat
Notes
Cold-sensitive — never let it drop below 10°C.
